Handling CO₂sorption mechanism in PIL@IL composites

The mitigation of climate change effects requires the use of alternative materials and technologies to control CO₂atmospheric levels through its capture, storage and use. In this field, the current work presents the evaluation of two poly(ionic liquid)s (PILs) (poly-1-vinyl-3-ethylimidazolium acetate and hydroxide) combined with free ionic liquid (IL) 1-butyl-3-methylimidolium acetate (BMI·OAc) for CO₂capture. The sorption capacity of PIL@IL composites was evaluated under 20bar of CO₂at 298K. Nuclear Magnetic Resonance (NMR) spectroscopy allowed quantification of CO₂sorption (physisorption and/or chemisorption) and in situ study of the PIL-CO₂interaction mechanism. NMR in combination with Molecular Dynamics (MD) simulations suggested a 3D organization of PIL composites, maintaining a similar organization to ILs. Also, the use of aqueous solutions of PIL@IL composites was tested, identifying the optimum conditions for water activation (intrinsic water trapped inside IL structure) for chemisorption. As our main contribution, we demonstrate the possibility to control the sorption pathway towards CO₂physisorption, or CO₂conversion (chemisorption) through carbonation (HCO₃^-/CO₃^2-) according to the PIL/IL ratio, ions structure and water amount. The use of PIL/IL composites is a promising advance for further CO₂reuse approaching a biomimetic carbonation process.